Whats a SONE?

Sone is a unit of measure of loudness and is equal to 40 Phons (Another unit of loudness). How different kinds of sounds we hear in everyday life would be scaled on the scale of Sone? One could get a vague idea of it with the help of following examples.

  1. A jet that’s 100 meters away from you would generate loudness of minimum value: 128 Sone and a maximum value: 1024 Sone.
  2. A TV set placed 1 m away from you would generate loudness of approximately 4 Sone.
  3. A normal human’s calm breathing would generate loudness of approximately 0.02 Sone.
  4. A normal talk being made at a distance of 1 meter from you would generate loudness within the range of 1 Sone to 4 Sone.



“The sone is a unit of perceived loudness proposed by Stanley Smith Stevens in 1936. In acoustics, loudness is the subjective perception of sound intensity. It is a non-SI unit.

According to Stevens’ definition,[1]a loudness of 1 sone is equivalent to the loudness of a signal at 40 phons, the loudness level of a 1kHztone at 40dBSPL. But phons scale with level in dB, not with loudness, so the sone and phon scales are not proportional. Rather, the loudness in sones is, at least very nearly, a power law function of the signal intensity, with an exponent of 0.3.[2][3]With this exponent, each 10 phon increase (or 10 dB at 1 kHz) produces almost exactly a doubling of the loudness in sones.[4]

Source: http://en.wikipedia.org/wiki/Sone